Parafin blowlamp

Needing to anneal some larg(ish) bits of brass I dug out an old 'Monitor No. 25' blowlamp from the back of the shed.......Not surprisingly it failed to light after 30+ years! I made new leather washers for the pump unit, cleaned jet with 'pricker', followed lighting gig with meths etc and generally examinied everything but still fails to light......

I'm not sure that the pump is actually pressurizing the tank (despite nice new leather wahsers)...and, looking the thing over, several questions have begun to from;

1) How does the pump pressure the air in the top of the tank when the end of the pump is below the parafin...(tank filled the required "three parts full"...?

2) how does the pump pressurize the air in tank if the fill cap has an air vent(which it appears to have)?

3) Anyone know if service kit is available anywhere for Monitor No.25?

Someone on this great site knows all about blowlamps and I don't like to admit I'm struggling a bit here......

1) Has a tube going from the base up to the top of the fuel tank.

Dunno about the others.

I collect camping stoves that work on the same principal, in the bottom of the pump there is a one way valve, its likely to be stuck open so you wont be able to get any pressure, check that the seals for the nozzle dont leak as well.

Martin P

1. If you blow air in at the bottom of the tank, the pressure will increase - it doesn't matter that this is full of paraffin - and the bubbles will rise to the top.

2. There should be no air vent - in the sense that a mower or motorcycle has - there should be a screw-in pressure release valve which allows you to 'switch off' after use. If your release valve is missing its pointy-ended scrwew you will never get up to pressure.

3. Don't know.

You can tell that the pump is working by listening for the squeak as the bubbles rise, and feeling the load on the pump handle getting harder as the pressure goes up. Much like a bicycle pump.

The valve in the pump is often a cone on the spindle which fits in a matching taper in the piston. Easy to sort, usually.

Hope this helps

Cheers, Tim

have you put some vaseline on your leather washers? i was always told to use it as part of a service on types that used leather

Kevin

If the blow lamp is cold and pressurised you should be able to squirt some paraffin out of the jet.

If you pressurise it before it is hot enough and the meths around the heater loops is still burning you can shoot a jet of burning paraffin out. I have seen this done with a Primus stove which works on the same principle, straight up onto an awning that was rapidly destroyed , so be careful where you point it. Fun in the scouts, good job it was not a tent.

I don't know what instructions you have but it should include reference to the vent. Heat the thing up with the vent open, just before the meths burn out close the vent valve and apply a small amount of pressure. The paraffin should be vapourised and burn as it comes out of the nozzle, if it remains liquid the heating process has not got everything hot enough so open the vent to release the pressure at that point. Do not add more meths unless you are absolutely sure there is no flame or nasty burns may result. If the paraffin is vapourised and burns pump a bit more but not too fast, you don't want to blow the flame out, gradually bring the pressure and thus the heat up to a point you can use the blow lamp. My dad always preheated the burner area with a gas hob to make the lighting easier, this is without fuel in it for safety. My uncle had a petrol blow lamp and that sounds far too risky to me, cold paraffin is a lot harder to have an accident with.

Martin

I slightly disagree with above in that I have a closed vent and a small amount of pressure in the vessel, I heat with meths until the meths is nearly gone and then I pump to get the pressure up more and they usually start straight away, once the burner starts to roar stop pumping then occasionally pump to maintain the pressure.

Martin P

Pricking the jet just pushes the debris back into the delivery pipe and it inevitably comes back again to block the jet. If your problem was caused by a blocked jet, far better to unscrew the jet and clean it out backwards. Then pump a slug of paraffin through the delivery pipe to clear any remaining debris. After 30-odd years I would be inclined to flush out the whole tank and load it with fresh paraffin.

That said, the non-return valve in the pump sounds a likely culprit (it might even have debris trapped in it...)

George

Hi

On my paraffin blow lamp which my father used some 60 yrs ago to thaw out frozen water pipes in the outside toilet when it failed to pressurise it was the valve in the pump but it was part of the plunger which has to be free on the shaft, mine was jammed after freeing it it works ok. I light mine with my small gas torch.

Stan

Thanks so much for all this excellent info!

The end of the pump tube (that goes in the parafin) is the part that presumably has a non-return valve........It bears the marks of a pair of pliers being used on it sometime in the dim and distant by members of my family now long gone......don't know if that's significant or not (the plier marks I mean!).

Tomorrow I will try to strip down the pump tube assembly and see if that improves things. I need much better heating equipement as my gas torches are woefully lacking for what I'm trying to do!

If anyone knows anything else useful I would be most grateful but thanks again so far!

The pump washer you need is a CUP form, try here:- **LINK**

although they are for Tilly lamps, there should be the size you need listed.

Nick

If you can't buy a washer the right size, it is possible to make your own, the leather from the tongue of an old shoe is about right.

My old lamp is a petrol one (about 1/2 pint size), the last time I used it the valve leaked and ignited, I dropped it onto my toe and kicked it across the yard, when it cooled down I put it away and got a gas bottle and torch.

Ian S C

Do you want to re-enact one of those WW2 movies where they use flame-throwers ?

Just buy a decent gas torch and hire a bottle , much quicker, cleaner , safer.

Nothing wrong with a paraffin blowlamp . You need to strip it and clean out thoroughly. A new pump washer can be made, see Ianc above. Half fill and close vent plug, pump gently and should see liquid come from the jet, and nowhere else. If all is well dry surfaces and fill the well with meths , light meths and when nearly burnt away and the tube is hot close the vent and slowly pump until flame is lit. I tend to use a rag or the proper clamp thing instead of meths. There are a lot of different lamps with small differences but all use same principles. Use it outside for safety, until you are familiar with it. They can be very useful for extra heat when s. soldering etc.

....Once more, thank you to all contributors,....your info is much appreciated.

Unfortunately I have not been able to persuade the non-return valve to part company from the pump tube and think that I'm not the first person to try! the end of the tube (with valve) is now soaking overnight in WD40

Since the efficiency of parafin has been slightly questioned by an earlier poster I feel a comment on blowlamps for people like us is worth mentioning. I have smaller gas/spirit torches and two forges/welding etc. For heating and working on brass components of medium size the parafin blowlamp is quite a nice addition to a workshop as it offers plenty of heat for not much money...a gallon of parafin costs a LOT less than a couple of tins of gas for my Rothenburger torch and, once I get the thing working, vastly better heat efficiency/run time.....

If I can't resucitate this blowlamp then I shall certainly look around for another specimen and have for some time considered it a very useful addition to my 'stuff'.......

Bob,

I use my paraffin camping stoves regularly, if I do use a gas stove it goes through the canisters quickly where as paraffin lasts for a long time and produces greater heat, the burner can easily glow red.

Martin P

Bob

I think you will find that paraffin has a very hot flame compared with gas.

Stan

If the valve chamber is brass and it didn't free when sitting in paraffin then I don't think that WD40 will help. Instead tap the joint maybe with a brass bar keep tapping and it will break open the joint.

I still use blowlamps for some jobs. Gas torches are very convenient for most soldering and brazing tasks but for boilermaking the soft bushy flame of a blowlamp is wonderful for getting heat into the copper.

I use modern blowlamps rather than antiques. Yes, they are still made because butane and propane gas are not readily available in all parts of the world.

The blowlamps I use are made by Motor Sich. They are made from steel and while they are primarily designed to use gasoline, by changing the jet size kerosene can be used as an alternative fuel.

The very comprehensive instructions include not only how to use the lamp but also maintenance, troubleshooting, and complete testing procedures. Helpfully, they are bilingual being written in both Ukrainian and Russian.

Those of a nervous disposition who have only ever used butane powered DIY gas torches may find a sudden and pressing need to change their underwear when using one of these for the first time...

Edited By David Standing 1 on 13/04/2017 23:49:38